Costa Rica's Tropical Forest, June 2002

Tom Davis

Last Updated: July 5, 2002

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This page documents only the first half of the trip; to read about the second half, click here.

The Project

I had previously been on eight Earthwatch trips and was looking for something to do. A few years ago I met a friend, Freddy, on one of them, and we decided that we'd do another one together. Freddy is very interested in volcanos, and wanted to go somewhere where he could see a lot of them, whether they are part of the project of not.

We decided that Costa Rica would be a good spot since the entire backbone of the country is volcanic, and since there are a lot of Earthwatch projects there. Both he and I had time constraints, and those pretty much decided that if we were to do one together, it would have to be the "Costa Rica's Tropical Forest, Team II" project. It seemed reasonable from the expedition write-up, so we just went for it. Freddy's girlfriend, Barbara was coming with him, and my wife planned to come down and join me after the expedition when the four of us could spend ten days or so, goofing off as tourists after the end of the official project.

Besides, the project took place in a region of Costa Rica I had never visited before in the northwest corner, near the Nicaraguan border.

The main goal of the project was to study the predator-prey relationships between the prey (caterpillars) and their predators (primarily wasps, spiders, and ants). The caterpillars are primarily up in the canopy, so it's really tough to count them, but there is a fairly easy way to measure their total activity: measure the number of leaves they eat. Of course the leaves are also in the canopy, but after they enter the caterpillar through the mouth, a relatively high percentage of them leave the caterpillar from the opposite end, and the resulting "pellets" are called "frass". It was obvious from the first that this project would provide lots of wonderful opportunities for language play.

There were some secondary projects going on as well being investigated by the same investigaor, and a couple of those will be discussed later on this page.

To measure the amount of frass rain, the principal investigator for the project, Eric, had set up four pairs of sites, where each site consisted of thirty frass traps. A trap is simply a sheet of plastic approximately 85 cm square, held off the ground by four metal wires. The plastic is not stretched tightly, so a small (clean) rock placed in the center causes it to take a shape that tended to catch the falling frass and move it toward the center.

Dirty trap Frass trap

Frass Traps

Here are a couple of images of frass traps. On the left is one that needs cleaning. It's full of water, mud, leaves, and dissolved frass after a rainstorm or two. On the right is Peter, posing with a perfectly clean trap -- enough to bring joy to the eyes of any dedicated frasser.

Each trap site consisted of five rows of six traps, arranged, as closely as possible, on an orthogonal grid with ten meter spacing along each row and column. Thus they should, on average, sample the forest somewhat uniformly. Some happened to be under trees with lots of leaves, and some were in the open. With 240 total traps, the collection should be pretty representative.

Eric wanted to have a 24-hour collection from each of the traps, and to do this each month of the year so he could plot the relative numbers of caterpillars (or at least the relative biomass of those caterpillars) over the course of a year and compare that with other years. Obviously, in a year with an El Niño event, there will be a lot less rain in Costa Rica, so the numbers of caterpillars will probably be quite a bit lower than in a normal year. Our team was to collect the data for the month of June, 2002.

The People

I already knew Freddy and had heard a lot about Barbara. Freddy and I had done the Ecuador Birds project over the 1998/9 new year. I arrived in Costa Rica a day early and Freddy, Barbara and I went on our own expedition to visit the top of the volcano Irazu, near the town of Cartago, perhaps 20 km to the east of San José. On the evening of the Irazu trip, we met all the other volunteers as well as Eric, the leader of the expedition. Group

Group Photo

Here is most of the volunteer group, with only Cobie and Jenny missing. We're posed in front of one of the largest strangler figs I have ever seen. The photo is by Dale, whose job was made harder by the fact that we were standing right in the middle of swarming leaf-cutter ant soldiers. Dale took a bunch of versions of this photo, but most have one or another of us slapping at our boots to get rid of the ants. From left to right: Peter, Jean, Ron, Sue, Steve, yours truly, Joseph, Freddy, and Barbara.

The team included 5 Brits, all of whom had won a "Millennium Award". They were a husband and wife, Ron and Jean, as well as Sue, Steven, and Peter. All were around my age (53), I'd guess. There were three younger folks as well: Joseph, from Canada, and Jenny and Cobie from the United States. Jenny was only 16, and was probably a bit nervous about going on a trip with all the old geezers. This was the first Earthwatch expedition I have ever been on where the US citizens were in the minority.

It was nice to get get a more balanced (at least in my opinion) perspective on the world situation than what you get in the United States where flag-waving lunatics seem to be in total control and hell-bent on giving up all their freedoms in order to "fight terrorism". In fact, quite a few times when various people wanted to make a statement about how stupid somebody was, it was stated in the form, "He's almost stupid enough to be president of the United States."

As is almost always the case on Earthwatch trips, everyone seemed very reasonable, unlike most packaged tours I've traveled with.

We met at the Kekoldi hotel near downtown San José and after a short period of introductions, Eric led us to a get-acquainted dinner at a nearby restaurant. Of course when we got there, it was open, but closed to us. All the seats were reserved for the most important soccer (football) game in the world, Costa Rica versus somebody in the World Cup. But since the game didn't begin until 1:30am, Costa Rica time, Eric was able to talk his way in, promising that we'd be out well before 1:30 (it was perhaps 8:00pm when we arrived).

We were out in time, but it was pretty interesting to watch the football crowd drift in. Most were wearing the Costa Rica colors, there were lots of bodyguards in case of fights, there were plenty of scantily-clad women/cheerleaders to hand out flags, et cetera, and most men were frisked as they came in. I sort of wished we had been able to stay to see what happened. Jenny, Cobie, and Joseph did remain for a while after we left, but I don't think they saw any interesting fights or anything (or at least any that they told us about).

I was sort of glad to have an internal room at the hotel, since I had once had a street-facing room in Guayaquil, Ecuador, when the Ecuador soccer team won an unexpected game against some powerhouse. All night long the cars circled the hotel, honking their horns repeatedly. I guess Costa Rica won that night, but I was able to sleep through the celebration. Those with the street views were not so lucky ...

In fact, the World Cup remained a key topic of conversation for the rest of the trip which was a little tough on me, having never watched a soccer game in my life, even on TV. Since the games were in Korea and Japan, they all took place at either 1:30am or 5:30am, Costa Rica time. Toward the beginning of the tournament there were games at both times almost every day, and many fanatics stayed up to watch them both. Needless to say, quite a few shop owners appeared to be pretty stunned when we'd go in at, say, 8:00am.


Row of Mushrooms

Here's an artistic set of mushrooms arranged on a log that we also found on our day-off trip to eastern Costa Rica.

In addition to the 11 of us volunteers, Eric had two assistants, Dale and Elvin, whom we saw almost every day. Dale's wife, Sasha, was also there, but working for another group, but we also saw her on most days. Elvin is a Costa Rican who lived in the nearby (40 km away) city of Liberia. Finally, a woman named Kuniko worked in the lab and was a truly fabulous technical artist.

Kuniko is working on a book of illustrations of the jumping spiders of Santa Rosa, and her drawings are absolutely mind-boggling. I think she works for two to three days on each drawing, looking at the spider under a microscope to draw almost every tiny hair on its body. She had already completed approximately 70 such illustrations. In our spare time, we could beat the bushes looking for other examples of jumping spiders, trying to find species that she had not yet illustrated. Even though she was not officially associated with the Earthwatch project, we saw her every day, and she joined us for many of our extracurricular activities. In addition to being a great artist, she is extremely knowledgeable about the general biology of Santa Rosa where she has worked, on and off, for years.

When scanned and placed on the web, her drawings are nowhere near as beautiful as the originals, but some scanned versions can be seen here: Spiders.

Joseph was also a very interesting guy. Although he was also quite young (19), he had an amazing knowledge of anything related to archeology and mythology. He also had a huge number of interests in other areas, many of which overlapped with my own particular bizarre collection. I remember once getting in "trouble" when Dale was telling the group about something and he yelled at Joseph and me to quite talking about linguistics.

To Santa Rosa

Our project took place in the Guanacaste Conservation Area, a part of the northwest corner of Costa Rica that includes the national park at Santa Rosa where we were. Santa Rosa is famous because it is the site of the Casona—a building where the American William Walker and his army of so-called "filibusteros" who were invading Costa Rica so that Walker could become the king of Central America were stopped by a collection of Costa Rican volunteers. Most of the real Casona was burned about a year ago by poachers in the park who were upset at their punishment, but every effort has been made to duplicate the building exactly as it was. Our research site and dorm was within about a 10 minute walk of the restored Casona, which I had never seen before.

Apparently there is a big problem in Santa Rosa and other parks in Costa Rica with this sort of thing. Obviously, when a region becomes protected as a national park or something similar, the farmers and ranchers in the area are thrown out of work. The government attempts to re-employ as many as possible, but obviously that's going to be a small percentage. In retaliation, there's a lot of poaching and intentionally-set fires. In a park like this one that can be tinder-dry in the dry season, the fires can do a tremendous amount of damage. It's hard to know what to do, however. Costa Rica, although it's pretty rich compared to its neighbors, is a poor country, and it's hard to get money for conservation from first-world countries, who would prefer that any money loaned to a country come back immediately in the form of military hardware purchases as is done in most other Central and South American countries.

Eric rented a bus, and we took a very leisurely ride from San José to Santa Rosa, stopping at the Mercado Central in San José, as well as a spot near Cañas for a nice picnic, at a restaurant for refreshments, and probably a couple of other places that I've already forgotten. We sampled all kinds of interesting fruit, and Eric was great at pointing out interesting plants on the way up, and at each of the stops. I think Eric wins the prize, so far, as the Earthwatch investigator most concerned with the happiness of his volunteer crew.

At the picnic spot we were right next to a nice river, and many of the folks went in for a swim. Since it was so hot, it didn't really matter if you went in with your clothes on, since they would quickly dry afterwards, and since nobody had their swim suits handy, that's what most did. Jenny, however, probably should have taken out her passport before the swim ...

On the trip out, Jenny was seated near me on the bus, and was pretty amazing for a 16 year old—she was totally confident in conversation, et cetera. I would have withdrawn into my shell had I been in her position when I was 16.

When we arrived, the first order of business was to unpack our stuff. We had two dorm rooms, each containing 4 bunk-beds, or 8 people. I shared the room with Ron, Jean, Freddy, Barbara, and Sue. When Sue lifted her mattress to install the sheets, she came face-to-face with a nasty looking scorpion! I had a pair of giant tweezers and we tried to grab the scorpion to remove it from the room, but it escaped to somewhere between Sue's bed and the wall. Since we were only using six of the eight beds, Sue reasonably decided that the scorpion bed must not be hers after all, and she switched to one of the free ones.



Jean found this little fellow swimming in the sink when she was washing a few dirty clothes. Obviously, it had hidden between a pair of socks or something. Luckily, she was washing it rather than trying to put it on. After a few near-misses with these guys, everybody was shaking clothes, boots, et cetera, before putting anything on.

All in all, there were plenty of scorpions to be found, and you would see two or three of them every day. The image above shows one that Jean found in her dirty clothes, and Eric's assistant, Dale, found one with his fingers when he was picking up a teacup in the lab. The stings are nasty, as Dale can testify, but apparently unless you're allergic to them or something, they "merely" deliver a very painful sting. Needless to say, everyone took a great interest in shaking out clothes and boots every morning before putting them on.

Although the scorpions and snakes (described later) were a little scary, what was really annoying from time to time was the mosquitos and chiggers. Everybody had a few bites and some folks got totally nailed. I have for years used a chemical called permethrin on my clothes, and one application seems to last for a couple of weeks, even when I wash, or at least rinse, the clothes every day. Because of this, I think, I got far fewer bites than the others. I also learned about a special preparation of DEET that's more effective than most. It is put out by the Sawyer company, and is in tiny "micro spheres". Regular DEET evaporates rapidly, so many reapplications are required. The Sawyer stuff says that it works for 24 hours. I doubt that, but it sure seems to work longer than ordinary DEET, and is also at a much lower concentration. The Sawyer stuff is about 20% DEET and the other stuff can be up to 100%.

There was just an article in the paper a day or two ago, and the most recent tests (as of about July, 2002) still indicated that the only chemical that really seems to work against insects in double-blind tests is DEET.

One other nice feature of permethrin is that it also keeps out ticks and chiggers (of which we encountered quite a few as well).

I am not immune to chiggers. On the second part of this trip we spent some time at another research station, where I played a single game of soccer. This was the first time I went outdoors in the jungle with less than a long-sleeved shirt and long pants, and I remembered to smear every square inch of my skin with mosquito repellent. But I didn't smear my socks with anything, and after only one hour of playing, I found perhaps 200 chigger bites between my ankles and my toes. And they really itch!

Frass Cleaning, Collecting and Processing

The 240 frass traps are arranged in pairs of sets of 30 in four slightly different forest types. The drill was this: go out in the morning and clean all 60 traps in a pair of sets, and then wait for 24 hours praying that it will not rain. If there is no rain, return the next morning to collect the frass in each trap in a separate small petri dish. The material in each dish is dried, and then sorted to remove the debris from the frass. Finally, the weight of the frass in each petri dish is determined and recorded. The goal was to obtain one 24 hour sample from every trap sometime during the month of June.

Eric and Jenny

Eric and Jenny

Our fearless leader, Eric, brandishing a filthy frass-trap rag, explains to Jenny how much fun it is to clean slimy caterpillar shit from a dirty trap. Jenny is not so sure.

When we began, the traps had all been unattended for at least a month. Since the rainy season had already begun, needless to say, all were full of water, mud, leaves, sticks, and all sorts of other junk. To clean a trap, all that material had to be removed and then the plastic was dried with rags and finally with a paper towel to remove almost all of the moisture. The problem with moisture is that if frass falls into a wet trap, it disintegrates and looks just like mud. Dry frass pellets are fairly easy to recognize. Although it is one of the largest frass pellets, the example from the large sphingid caterpillar in the image below gives some idea of what all frass pellets look like.

Sphingid caterpillar

Sphingid Caterpillar

This giant caterpillar was one of the largest we saw. In the image, you can see one of the correspondingly large frass pellets.

Each array of thirty traps was normally numbered A1, A2, ..., A5, then a parallel row of B1 through B5, and so on, to F1 through F1, for six rows of five traps each. Trap A1 was generally on a trail, but the others were set on a grid so that the distances between any adjacent pair of rows or columns was as close to ten meters as possible. Thus any servicing of the frass traps required a fair amount of cross-country bush-whacking.

For this reason, we were all required to wear either rubber boots or "polinas"—leather devices that wrap around the leg from the base of the boot to just below the knee. I preferred the rubber boots, since then I could also wade through puddles and mud with impunity, and they were easier to put on and take off. Unfortunately, most of the volunteers did not bring boots and used the polinas instead.

Hognosed viper Hognosed viper

Hognosed Viper

Here are a couple of images of a small, poisonous snake that seemed to be pretty common. It's called the "tamagá" locally. I saw three of them.

As can be seen from the images above, the polinas or rubber boots were a very good idea. There seemed to be a lot of these little hognosed vipers around, and they liked to lurk in the areas where the frass traps were set. We were all instructed to look carefully under the traps before reaching under them to lift them up for cleaning, et cetera, and in general to look carefully before touching anything on the ground. In spite of this Barbara got a pretty good scare. She checked under her trap, found nothing, so removed the stone from the center and set it off to the side. She then carefully cleaned and dried the trap (which probably took a minute or two), and then picked up the stone to place it back on the plastic sheet. During that one or two minutes, a hognosed viper had curled itself around the underside of the stone, and she came within millimeters of touching it!

Although these snakes are probably too small to kill any of us, as Eric said, "A bite would certainly ruin your day."

After 24 dry hours, we returned to collect the frass from the traps. Since everything was dry, it was quite an easy process to remove the larger leaves and other obvious debris from the traps and to scrape the frass pellets and other junk to the center of the plastic. Then all that material was put in a small petri dish perhaps 4cm in diameter and .75cm deep. A slip of paper was placed in each dish that included the trap number and the site number, and all thirty dishes were closed with elastic bands and returned to the lab for drying.

Sounds easy, right? Well, there was one thing we never got right, and that is that we never learned properly to pray for no rain. During the first week, it seemed to rain, like clockwork, every afternoon, and not just a little rain; it rained buckets. So the next morning, we'd go out and re-clean the traps for the day before and try again. Cleaning the traps was not a big deal, but most of the sites were a fair hike away from the lab, so most of the time was spent hiking to and from the sites. Also, since we were beginners, for the first few cleanings either Eric or Dale wanted to be with us, so we couldn't split the group into a bunch of smaller ones to get to a large number of sites. At the beginning, we usually only cleaned one pair (60 traps) at a time, so four complete cycles would be required to get a 24 hour sample from each of the 240 traps.

In fact, in desperation, Eric had us collect a couple of 8-hour samples if it had not rained by the afternoon. We'd do a regular collection, but early, and leave the petri dishes under the plastic sheets. Then, if it happened not to rain at night, the plan was to go the next morning and add the other 16 hours worth of frass for a complete 24 hour collection, but if there were rain, at least he'd have a 1/3 size sample. He didn't want simply to multiply the 1/3 sample by 3, since there's no guarantee that the caterpillars eat at a constant rate. They may slow down or speed up at night because of changed temperatures, fewer or more predators, et cetera.

It did get pretty discouraging to set the traps in the clear morning, and then watch the clouds slowly gather, and finally let loose in the afternoon or at night. The funny thing was, we started setting traps in the other areas so we would learn where they were, and eventually had complete 24 hour collections from all the traps but the very first set that we tried. In fact, we got two 8-hour collections from those traps before finally being lucky on one 24 hour period very near the end of the two week volunteer period.

As soon as we got a good set back to the lab, all the petri dishes were placed on a tray with their lids off and placed in an "oven" kept warm by a few lightbulbs, and after 24 hours or so in there, the material was pretty dry. At this point, the frass sorting could begin.

Sorting frass

Frass Sorting

Here on the left is the result of a successful sort. The petri dish on the left is full of frass pellets, and the one on the right is waste -- tiny twigs, leaves, dead insects, and who knows what else. Below, you can see the tips of a pair of tweezers for picking up the larger pieces and the tip of a paintbrush which is used for the tinier items.

Graded Frass

Graded Frass

It's hard to say exactly what got into him, but one day during the frass sorting Ron cracked, and did far more than simply sort the frass from the non-frass. He actually graded it into different sizes as a sort of sick pedagogical tool for future frass sorters as shown in the image on the right. I think of it more as a warning of what can happen to a perfectly sane man's mind after doing too much of that sort of work.

To do a sort, each of us sat at a table with a sheet of white paper, a lamp, magnifying glass, some tweezers, and a paintbrush as well as one petri dish filled with dirty frass—frass mixed with other stuff. The material was poured out on the paper, and all the frass was returned to the dish while the non-frass waste was collected in a waste bin. Eric liked to look through the waste to assure himself that a reasonably good job of sorting was being done. The use of the tweezers is obvious, for fairly large particles. The paintbrush was perfect for tiny ones. If it was slightly dampened, it could easily pick up tiny specks or either frass or garbage to be transferred to the appropriate pile.

Sometimes it was easier to pick the frass out of the garbage and sometimes the garbage out of the frass, depending on the relative amounts of each. Sometimes if there had been just a tiny amount of rain, we collected the frass anyway, but that stuff was a real pain to sort since the particles were often effectively glued together. Most dishes took around a half hour to sort, but some took quite a bit more. In an afternoon, the 11 volunteers could usually do 60 dishes without too much trouble, and not everyone had to work all the time.

It was a bit boring, however. Sometimes hardly enough to keep the mind alive, so we all concentrated on making up frass jokes, which turned out to be quite easy to do. There was also a cassette tape player available with a fairly limited range of tapes, and it's entertaining to imagine how easy it was to find music that was acceptable to a group that ranged from a 16 year old girl to a bunch of geezers in their 50s. You'd just suffer through one tape and insist on your own for the next one.

Shit for brains

Shit for Brains

Here is a photo of the author, after having been driven insane by too much frass sorting, "snorting" lines of the caterpillar frass. Thanks to Dale for helping to set up the shot and for taking the photo.

As the image above illustrates, sometimes the strain became too great and some of us cracked under the pressure.

After a sufficient number of petri dishes were cleaned, a pair of us would go off to the weighing room to find the weights of each sample. Eric had a nice scale, but apparently it had gotten more and more finicky as it spent more time in the tropics. Although some days it would repeat measurements over and over to an accuracy of 1mg, some days it would vary by tens or twenties of milligrams between two weighings of the same thing. There were lots of problems: the temperature varied all the time, it was hot in the lab so there were sometimes fans running, the humidity was always high, maybe it even depended on the phase of the moon, but sometimes it worked and sometimes it didn't.

Barbara and I were the weighing team one day, and I managed to spill a bunch of frass on my lap from one of the dishes. I did not want to move for fear of spilling it on the floor, so Barbara tried to pick out all the pieces with a pair of tweezers, and the scene seemed so funny to us that our laughter reached a point where it was almost impossible to continue. Finally, I think we managed to get 99% of it or so...

At one point during our stay a group of college kids who were taking a tropical biology course came through the research site and spent a few nights there. When they first arrived, we observed a bit of strange behavior: multiple screams from their dorm rooms, and later, much louder screams from the showers. This was all explained to us later.

During a lunch period, a gal named Jennifer from the group came to our table and asked what we were up to and if she could volunteer to help. It turned out that although she was with the group, she was sort of auditing the course since she had graduated early, but went along with the trip because she had a lot of friends who were still in school and besides, who could skip a great trip to Costa Rica? She explained all the mysteries to us.

The kids all came from a college in South Carolina (whose name escapes me) whose mission was to enroll kids who were the first in their family ever to attend a college. They mostly came from an isolated county in South Carolina, most had never been out of the country, and one had never even been on an airplane.

But many of them apparently also had never seen a cockroach in their rooms, and if there was one thing that was absolutely guaranteed, it was to find plenty of cockroaches running around at any hour of the day or night. We prayed each night for an army ant raid to enter the dorm and clean it out, but none of those prayers were answered either...

Army ants

Army Ants

Here is a tiny portion of an army ant raid that is passing over a broken plant stem. Click on this photo for much better detail of the ants.

The loud screams from the showers later on were because apparently none of the kids had ever had a cold shower, either.

But Jennifer was really great. She threw herself into the task of sorting frass and was even able, after only a day, to make up some perfectly acceptable frass jokes. Also, during that day we had a set of traps out for which we were hoping to get an 8-hour collection, and suddenly the clouds started moving in. In a couple of minutes, we put together an "emergency response team" that raced out into the field, and Jennifer came along with us to get soaked and muddy.

Jungle Travel

All the frass traps were within walking distance of the lab, but to reach some of them required a significant amount of walking. To reach the Santa Rosa buildings from the main road (the Pan-American Highway) there was a paved road that's in fairly decent condition and in addition there are a few shorter dirt roads that lead to various places. The hike to any of the sites began (or at least could begin) with a short stretch on a road. Some sites involved fifteen or twenty minutes on the road before you had to set off onto the muddy trails.

To save time, Eric had a bunch of bicycles, and particularly if we were working on the northernmost sites, we'd begin the trip on a bicycle. We'd then hide the bicycle off the road, and continue to the traps on foot.

I used bicycles once before in Costa Rica on another Earthwatch project when we studied caterpillars at the Organization for Tropical Studies (OTS) station at La Selva, and I now have a general theorem about them (about bicycles, that is). Rainforest bicycles are always in a state of almost total disrepair, and this is not because they are not maintained. It seemed like every other day some poor guy was sitting in front of the lab with a few broken, rusty bicycles and a toolkit.

A few of them always had flat (or at least leaking) tires, at least one pair of brakes didn't work on every bike, it was a total miracle if you could shift gears either on the front or the back, and sometimes there were even more serious problems, like the headset being so loose that the handlebars and front wheel moved almost independently.

I'm not the world's greatest bicycle rider, but on I bike at home I can put in 40 or 50 miles on hilly roads without too much trouble, and I found these bikes to be a nightmare to ride. Luckily things were pretty flat, but there were a couple of hills that required us to gain 10 or 15 meters, and I found myself standing on the pedals to get to the top of each of them. Maybe the fact that I was wearing rubber boots that came up to my knees had something to do with it, but that was surely only part of the problem.

Cobie apparently does a lot of mountain-bike riding and seemed to do pretty well, so maybe my problem is that I only ride those prissy road bikes at home. But they did get us to the sites quite a bit faster, but you would often return covered with bits of mud sprayed up by the bike in front of you.

Once we were off the bikes, we'd hike on trails or dirt roads. Before it became a national park, the entire area was farmland or ranchland, so it was criss-crossed by dirt roads. Some of the roads, however, became rivers or swamps after a good rain, and it was hard to know whether it would be easier to hack through the bushes and acacia just off the road or to hike through the muddy water, hoping not to find a deep hole. With my rubber boots I often found it easier just to hike on the road but for the others, wearing just boots and polinas, the off-road option was better.

Beating for Insects

The frass traps allowed Eric to obtain a measure of the number of active caterpillars, but we also wanted to find out how many predators there were in the areas near the frass traps. To do this, teams of two people would beat for insects.

This was accomplished by picking certain routes and beating the bushes with a stick at certain designated places within each ten meter stretch of trail. We'd carry a sheet of cloth spread like a kite over two crossed sticks and place that under the bushes before pounding them with a stick. All kinds of dirt, leaves, sticks, and insects would fall into the cloth trap, or on your head if you were beating high branches.

Then, one of the team members was armed with an aspirator (which we called a "pooter") which allowed him/her to suck insects from the kite-like cloth into a small vial. If the pooter was properly used, there were screens to keep the sucked insects out of your mouth, and you could, with just a little practice, pick them off the cloth pretty quickly. Freddy did verify that if you sucked on the wrong end that the insects indeed did go into your mouth.


Beating around the Bush

Here I am, beating the bushes with a stick and a piece of cloth stretched out on a kite-like structure. The idea is that you beat the bushes from certain places and catch as many insects as you can. You then collect the predators of caterpillars -- ants and spiders -- and count how many there are for each beating. This process is repeated by other groups at other times of year to learn how the number of predators rises and falls with the seasons and with the number of prey. Note the "pooter" (described in the text) around my neck, and how I am bravely standing in a streambed to sample the streamside insect fauna.

We were only interested in sucking up ants and spiders, and we also counted the number of caterpillars that fell onto the sheet. For a cross-check, we tried to count them as we sucked them into the pooter by repeating back and forth to each other a sequence of three numbers that represented the number of ants, spiders, and caterpillars, in that order, that we'd caught in that particular beating. For example, if we caught two ants in a row, followed by a spider and then another ant, the sequences (said by the pooter-bearer and then repeated by the bearer's partner) would be: "1-0-0", "2-0-0", "2-1-0", "3-1-0". I don't think we fouled this up too often, once we got used to it, and, after all, Eric had the real bugs at the end with which it could be compared.

Of course the spiders immediately started making webs in the pooter collector, and got everything very tangled up, so every half hour we'd put in some alcohol to wash them into a collecting whirl-pack. After doing this, the first couple of sucks on the pooter were enough to clear your sinuses, inhaling big breaths of freshly-evaporated denatured alcohol.

Barbara and I had a minor adventure while doing this beating. Eric noted that both she and I were wearing rubber boots, and wondered if we'd be willing to sample insects along a steamside instead of the usual trailside sampling. Of course we said yes since it seemed slightly more adventurous, and were directed to a stream a fair distance from the frass traps. (After cleaning the traps, we'd usually start there and beat the trails in various directions from them since we were there, and since it would obviously be a good idea to know about the predators near the traps where you collected the frass from the caterpillars that were, presumably, their prey.)

Eric told us that after beating, we would be quite near the road that led directly back to the lab, so it would be easiest if we just returned on the road rather than come back to the frass traps.

Well, it was hot and I had a heavy pack filled with all sorts of camera equipment and God knows what else, so when we started beating I just hid it in the bushes at the start of our collection. When we finished, we were, as advertised, near the road, but had to come back quite a bit to retrieve my pack. We decided that a hike home through the forest would be much nicer than one along the road so we decided to come back on the trails. We had a half-hour until lunch, so there was plenty of time.

We hiked back to the traps, and then Barbara's and my stories begin to disagree. I claim that she started confidently down a trail, and she claims that I was the confident leader. Anyway, we wound up walking on a very familiar trail, and very confidently. It was a familiar trail, but we were going in the opposite direction than we thought.

One problem with the research area is that it's full of rolling hills, and it's impossible to see any landmarks far away for long distance navigation. But we had a map, and the trails were labeled.

So when our trail crossed another, we confidently turned left where we should have turned right, so were walking directly away from the lab and lunch. We knew that this trail would, after a kilometer or so, run into a stream bed that we could follow to a trail very near the lab and we did, in fact, come to a stream bed after about a kilometer, and even more confidently, turned the wrong way on that. Since we were so confident, it took a lot of hiking before we were totally convinced that something was wrong, so we returned along the stream bed to the intersection with the trail and without looking at the map, confidently continued down the stream bed in the opposite direction, knowing that the trail to the lab must be within 100 meters or so.

But it wasn't.

We got out the map, and verified (assuming the very first turn had been correct) that the original direction in the stream bed was correct, and finally got puzzled enough to pull out the tiny compass that I have hooked to my backpack. North was south!

Then we noticed that from the original trail intersection there was, indeed, a stream bed a kilometer south of there, but that there was also a different stream bed about a kilometer north, and that's where we were. By now it was lunch time, and we had spent a half hour walking very confidently away from the cafeteria.

An hour later we got back, pretty wiped out, and managed to talk the wonderful cafeteria staff into giving us something to eat. After that, whenever Barbara or I would start out toward some destination, the rest of the volunteers would automatically start going in the opposite direction.

Spiders and Ants

I learned a lot about spiders on this trip. I think most of us have a natural aversion to spiders, and in general, we're much more averse to touching a spider than to touching an ant. Except for the fire ants, almost all the other ants in the United States are pretty harmless—maybe a small bite or sting is all you'd get. And of course everyone in the US knows about the black widow and brown recluse spiders whose bites can be bad news.

But in Costa Rica, there are lots of ants with nasty stings and bites. Eric and the staff would pick up almost any spider and play with it, but they hardly ever would touch the ants. After watching this happen for a while, I began to handle the spiders as well, and had no bad experiences. I did get a couple of nasty stings from the acacia ants, however, even though I was doing my best to avoid them. And since it's pretty easy to recognize the black widow and brown recluse spiders here at home, I think I may now be able to amaze and horrify my friends with spider tricks at home. Tarantula


Here's a little tarantula we found wandering around in the leaf litter. This is also the first tarantula that I ever picked up in my bare hands.


Leafcutter Ants

Here's a close up of some leafcutter ants (taken in a different part of Costa Rica on a different trip, but they're basically the same). Unlike the BBC, I am confessing that this shot was not taken at the same site to which the story refers. See BBC reference.

One interesting sort of ant that we could find all over the place is called a leafcutter ant. They live in huge colonies and gather little pieces of leaves that they use to culture a fungus that's used to feed the any colony. There are many castes, including a huge soldier ant. See the images above and below. A couple of folks got bitten by these soldiers and reported that it was no fun at all. We did see, although I did not get a photo of it, a column of leafcutters that was carrying only flower parts, so instead of a line of twinkling green bits of leaves, there was a line of purple parts of petals. Some leafcutters apparently carry little bits of twigs and other things.

Barber Ant barber

Ant Barber

Barbara said her hair was too long and was looking for someone to cut it a bit. We found a trail of leafcutter ants that included a few huge members of the soldier caste, and with great care, Freddy grabbed one and tested its jaw power on various twigs which it was able to sever easily. We then decided to try it as a barber on Barbara's hair. It certainly clamped down, and was unable to clip the hair, but it was also nearly impossible to remove. On the left is Freddy, cutting off the hair in the ant's jaws, and on the right is a close-up of the soldier with a death grip on the strands. Note the huge head, relative to the body size. The head is full of muscles to close those jaws.

Most times of the year, it's hard to find the soldiers—the columns of ants are usually made up mostly of worker ants hauling leaf fragments back to the nest. But for some reason, this time there were soldier ants all over the place, not just from one nest, but from many of the nests. Perhaps it was the period of time when the virgin queens leave the nest to mate and try to form new colonies.

Ant Acacias

The northwest part of Costa Rica seems to be covered with a certain type of plant called the ant acacia, or bullhorn acacia. There are two species, but one seems to predominate, the other being found mostly in wetter areas (which are hard to find in a dry tropical forest). In fact, I did not see the second variety at all in Santa Rosa, and only found it later in the trip when I was a tourist at the OTS station in Palo Verde, and there all the members of the other species I found were right near the Tempisque river.

Acacia Acacia

Bullhorn Acacia

Here are two photos of the bullhorn acacia plant. The shot on the left is of a thorn that has been hollowed out by the acacia ants. You can see the hole on the upward-pointing thorn. Ant larvae are raised inside the hollowed thorn. In the same photo you can see a set of nectaries on the branch to the left of the thorn. Ants obtain sugar from such nectaries and in exchange, guard the plant. On the right is an image of a newly forming branch, covered with incipient beltian bodies (food for the ant larvae) and heavily guarded by acacia ants.

This plant has a very interesting symbiotic relationship with the so-called acacia ants (of which there are three different species in Santa Rosa). The ants live on the plant, and in fact, hollow out the large thorns to use as nests to incubate their eggs and feed their larvae. In addition, the plant provides nectaries from which the ants can obtain sugar water, and on the tips of its new leaves, it provides tiny objects called "beltian bodies" that are, essentially, a perfect food for ant larvae. The ants live in the thorns, drink the nectar, and feed the beltian bodies to the babies. Interestingly, Barbara is from Belgium. Or maybe she's a Beltian, and those are Belgian bodies...

Plant Killer

Plant Killer

Here's a nice illustration of the acacia ants at work. The image shows a lone bullhorn acacia growing in a field filled with other lush green plants. But the area around the acacia is completely cleared—any time some other plant began to grow within a given distance, the ants cut and killed it.

In exchange, the ants savagely protect the plant. Almost any insect, caterpillar, or other herbivore (like even mammals) will be attacked by swarms of ants when the plant is touched. Even if a tendril from a vine attempts to attach to the plant, it is cut by the ants, and thus an acacia with a good colony of ants is quite protected. The ants even seem to clear away nearby foliage so the acacia gets as much sunlight as possible. A large healthy acacia tends to have a large healthy ant colony and vice-versa.


Beltian Bodies

Here is a close-up of a few beltian bodies attached to the ends of some of the tiny acacia leaves. There are three, for example, on the top three leaves on the right. The ants have removed most of them already to feed to their larvae. For size reference, the background is the woven material of a nylon back-pack.

When we were bushwhacking to get to the frass traps, we always took special note of where the bullhorn acacias were. If you brushed against one accidentally, it was likely that you'd get a sting or two from the acacia ants. I can testify that such a bite continues to sting for five or ten minutes afterwards.

The plants were also of interest to Eric, since although the healthy acacias are almost devoid of insect or spider life other than the ants, there was a certain species of jumping spider that seemed to live on many of them. Since Kuniko was drawing the jumping spiders, they took a good look at this particular species, and found that it only seemed to be found on bullhorn acacias. The more they looked at the situation, the more interesting it became, and Eric is currently trying to get a paper written for Nature that details all these findings.


One thing that made this trip different from all the other trips I've taken to Costa Rica (or to anyplace in the neotropics) is that I saw a lot of snakes. I'm not great at spotting them, and if I'm on a hike with a herpetologist, I'm always amazed at how many can be found.

Well, this time I found a lot, indicating that there must have been a tremendous number of snakes around, given the number that a herpetologist would have found that were invisible to me.

I have already mentioned the little hognosed vipers in the section on frass traps above.

The first night we were in Santa Rosa, Eric and Kuniko took us out on a "night hike" to look for stuff with our flashlights. We found a little colubrid in a puddle full of frogs which was pretty nice, but when we got back to the lab area, it was either Jenny or Cobie who spotted a fairly large coral snake slithering along the edge of the building. These are very poisonous snakes, but luckily, they are not aggressive, and are rear-fanged, so you're unlikely to get bitten. With that and the scorpion on the first day, everyone was put into the proper state of mind...

Cobie also spotted the snake below which looked initially a lot like another coral snake. It was climbing a tree, and I took a couple of photos when it was at the perfect height, but then discovered, to my dismay, that I'd had the camera in a funny, close-up mode and the shots were all blurred. By the time I had the camera set properly, the snake was above my head, so my shots were all taken without benefit of viewfinder, so in some sense, I'm lucky they are as good as they are.

Fake coral snake

Fake Coral Snake

Here's a crummy shot of an interesting snake we found. It looks superficially like a coral snake with a yellow-green belly and a red back, but ringed by small black stripes. Although on close inspection, the pattern is all wrong, initially, it seems very much like the deadly coral snake.

I also saw a couple more "racers" while I was there—I don't know exactly what they were, but they were greenish, perhaps a meter long, and very fast. They were clearly colubrids, and reminded me of the snakes we call racers at home, so that's what I call them here.

The most frightening snake we saw was during our trip on the day off to the other side of the continental divide of Costa Rica between the volcanos of Orosi and Cacao. It was a very different kind of forest—not dry, but definitely a rainforest. Eric takes all his groups there, apparently, and we saw lots of stuff, including two jumping vipers. See the illustration below.

Jumping viper

Jumping Viper

Here is an image of a fairly hefty jumping viper, locally called "mano de piedra", meaning "hand of stone". It was apparently in almost exactly the same place where Eric found it a month previously. The previous month, he had seen two, and while we were crowded around this one, someone noticed that he was almost standing on the other. Luckily, we were all wearing high rubber boots or the leather "polinas" that wrap around the leg from the boot to the knee to avoid snakebites. It would be quite nasty to be bitten by this guy!

After the Earthwatch part of the trip we saw other snakes as well, making this the most snakeful vacation I've ever been on.

Evening Entertainment

For the first few nights we were there, Eric delivered lectures on the various projects that he was investigating as well as on some general information about the area and the tropics in general. On the way to Santa Rosa, we had stopped at a huge grocery store in the town of Liberia to get some final supplies. I don't know what Eric got, but for us, the critical thing was a few bottles of rum.



Here's an inchworm caterpillar that is pretty well disguised as a twig on a tree.

About a half-hour before the first of Eric's lectures, Ron in our cabin made a very practical suggestion: why not open up the rum so each of us could have a "shot or two" to "take the edge off the lecture"? It was a truly inspired idea, and we even remembered to take the bottle along with us so that Eric himself could "take the edge off". Afterwards, we almost always got together in the evenings to "take the edge off", no matter what we were doing. What was nice is that there always seemed to be something to eat as well—somebody brought cookies or peanuts or potato chips or something.

At the research station in the main conference room there was a television with a VCR attached, and there was available a fairly large collection of videos, mostly on Costa Rican natural history. In Dale's other life, he spends a great deal of time working with a BBC film crew to capture various natural history topics all over the world. He had, in fact, just returned from Africa where they completed the shooting for a show on the army ants there.

Thus Dale was able to suggest some particularly good videos, mostly shot by his friend, some with, and some without Dale's help.

The first one was great—it was about Nancite beach in Costa Rica which (as the crow flies) is quite near the Santa Rosa station. It featured monkeys, jaguars, coatis, and all manner of other interesting animals. It seemed to concentrate on a troop of capuchin monkeys that lived near the beach and it described many of the interactions among the monkeys and between the monkeys and other species.

The second one would also have been great—if I had not seen the first. Not that it wasn't well done; it's just that it was about a different troop of capuchin monkeys in a completely different part of Costa Rica, and they used exactly the same footage in places. Being the general cynic I am, I guess I sort of expected this, but here it was, thrown in my face. The director had simply made up a story, and then found footage to make the story seem true. I now doubt everything I see on the nature shows. The behavior supposedly described in the two shows was completely different, but the footage was the same.

Nobody did any actual research on the monkeys—the director just decided what story the viewing audience would like to see and then told it, using film clips from any convenient place. And this is the BBC—one of the more "trustworthy" sources. I think the only solution now is to watch the shows with the sound turned off. For some reason, this didn't seem to bother other folks as much. Oh well...

When we ran out of videos, we continued to take the edge off in the conference room, generally with discussion sessions, singing, et cetera. It turns out that Steve, Jenny, and Peter had both memorized many songs, some of which other people knew. Steve had memorized many Tom Lehrer songs as well which he and I were able to perform as duets, to the amazement and likely horror of the others.

If you are interested in being amazed and horrified yourself, here is a link to a website with all the lyrics to all his songs. Although some of them are a bit out of date, many of them apply today better than ever to modern political fiascos.

Primate Studies

As it turned out, while I was there, I had taken as reading material a copy of Robert Sapolsky's "A Primate's Memoir", a largely autobiographical work that describes his work as a primatologist in Africa studying baboons, both as a graduate student and after he became a professor. Although there's not a strict alternation of chapters, the book generally alternates between a chapter or two on the baboons and their behavior followed by a chapter or two on Sapolsky's adventures.

It was interesting to read about the baboons and how they treated each others. Generally, they behave as total assholes. If a high-ranking baboon has a bad day, he'll beat up on a lower-ranking member of the troop or a female, and that baboon will beat up an even lower-ranking one and so on until the poor apes at the bottom are almost daily victims of abuse. Sapolsky studied stress, and the ones at the bottom exhibited almost all the same stress responses that we humans do, including not only behavioral responses, but similar changes in blood chemicals, immune system responses, et cetera. The baboons at the bottom of the dominance ladder had terrible health problems, were covered by parasites, and were generally miserable.

Then, after reading a couple of chapters, it became clear to me that the autobiographical chapters were the same. They basically illustrated that, although it's not quite so obvious, we humans also generally behave as total assholes towards each other, in situation after situation. Although the book was filled with plenty of examples, it became trivial to find as many examples as I wanted myself. When a big powerful society gets stung, it almost always "beats the hell out of" some weaker country. The US barracks get bombed in Lebanon or the the World Trade Center gets hit, so we attack and crush, Grenada, or Afghanistan. Or Israel gets some suicide bombers, so it kills many times as many innocent Palestinians. It doesn't matter that the perpetrators are hardly ever punished; human (or baboon) nature simply requires that someone be punished to make us feel better. And it certainly seems to work, as witnessed by George the lesser's current popularity in this country.

But there was plenty more to the book, including food sharing, flirting, friendships, coalitions, et cetera. I talked to Freddy a lot about what I was reading, and sometimes we'd see one or another of these sorts of things happening among various groups of people in the research station, and we'd both watch, and then mutter some comment about being the Santa Rosa primatologists. There was a limitless supply of material, but I won't go any further than that...

Time Off

As I said above, Eric arranged lots of events to amuse and entertain the volunteers. We went to dinner in Liberia to a pizza parlor, we went north almost to the Nicaraguan border to see a fantastic sunset followed by dinner at a tiny seafood dive on the beach, we spent an entire day traveling over a pass between the volcanos of Orosi and Cacao to visit a true rainforest on the eastern side of the continental divide of Costa Rica, and even on the last day, on our way back to San José, he arranged a trip to visit the Rincon de la Vieja national park.

Stuck jeep

Jeep in the Mud

On our day off, we took a jeep ride over a pass between the volcanos of Orosi and Cacao to the eastern side of Costa Rica. Obviously, from the photo, the roads were not great, but we only had to get out and push at one point.

The only downside of all the trips is that we spent quite a bit of time in the back seats of taxis on terrible roads, and I probably, in retrospect, would have preferred to skip one of the meals out, probably the one near Nicaragua, just because there was so much driving for just a sunset and a meal. They did have very fresh fish there, but it was all fried in lots of oil, so you couldn't really tell if it was fresh or not.


Nice Roots

On the way back to San José from Santa Rosa, we spent the morning in the national park Rincon de la Vieja. Here is an image of a wonderfully twisted set of butressed roots that we found there. Of course I have no idea what tree it is.

The trips to the rainforest and to Rincon de la Vieja, however, were wonderful, even though both required quite a bit of time on terrible roads. We saw lots of interesting plants and animals, including the jumping vipers mentioned above. We even had the dual adventure of getting the jeep stuck in the mud on the way up, and then of having to walk back through pouring rain when, on the way down, the jeep encountered a huge truck that was just parked in the middle of a very narrow one-lane road. Stinky Pants

Stinky Pants

When it was finally time to go home, Jenny was faced with returning some of her slightly soiled clothes to a suitcase. This image shows that it is not too difficult to do, at least if you have a long enough pair of tweezers and don't need to breathe.

All in all, it was a great trip, and I'm very glad I did it. The research seems like it's quite reasonable, I liked the working conditions, I learned a lot, met lots of great people, and was very impressed by Eric's efforts to keep us happy.

Freddy and I, however, are not satisfied. Although it was a good trip, we think we can do better, and are planning to submit some applications of our own to Earthwatch in the near future. Possible topics include: "The Pigeons of Rome", where we will study the pigeons of Rome from the windows of expensive restaurants. We may also look at the pigeons of Florence and Venice as well for comparative purposes. Another possibility is to study "The Yacht Culture of Monte Carlo". We'd experience the culture by becoming part of it for a few weeks. We'd also like to study the "Beaches of Bora Bora" and "The Nightlife of Berlin". These projects may be slightly more expensive than the normal run-of-the-mill Earthwatch project, however.

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Links to other Costa Rica Pages:

Photos of Costa Rican Animals
Butterflies of Costa Rica (Photos)
Travel Story—2001
Travel Story—2000
Weird Moths of Costa Rica (Photos)
Travel Story—1998
Travel Story—1997
Travel Story—1996

Links to other Earthwatch trip Pages:

Peru (Hummingbirds)—1999
Ecuador (Birds)—2000/1
Ecuador (Birds)—1999/2000
Ecuador (Birds)—1998/9
Costa Rica (Caterpillars)—1998
Ecuador (Birds)—1996/7